This supplemental request is for a technician to help maintain a breeding colony of mutant and control mice that will be used in the study of copper transport by isolated cells and in the isolation of a copper-binding protein. A request for a grant to study copper absorption and copper-binding proteins has been approved and funded for 3 years, beginning July 1, 1979, but the original budget was reduced eliminating specifically the full-time technician (Research Assistant II). As a result all of the work except dishwashing will have to be carried out by the Principal Investigator and his professional associate, Dr. Miller. This means a waste of professional effort and a marked slowing of the experimental work. The responsibilities of the technician will be to maintain the colony, including breeding, identification of mutants, help schedule experiments as a function of the availability of suckling mutants and controls, assist in the harvesting of tissues and help in carrying out experiments. With the aid of the technician, the functional and biochemical work proposed in the approved application can be carried out; without that help, work will be markedly slowed and less extensive.